[Bug c/60195] New: Strange warnings using atomic types

[Bug c/60195] New: Strange warnings using atomic types

[jp.deplaix at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60195

            Bug ID: 60195
           Summary: Strange warnings using atomic types
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jp.deplaix at gmail dot com

Created attachment 32134
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32134&action=edit
Test case

Two warnings are raised while compiling the attached test-case.

The first one in the function f:

warning: variable 'y' set but not used

but clearly it is. For example if you replace atomic_int by int here, the
warning desapears.

The second one in the function g at the line of « y = 0 »:

warning: right-hand operand of comma has no effect

this warning make no sense, since there is no comma at this line.


This was experienced with gcc 4.9.0 20140111 for the first warning and gcc
4.9.0 20140213 for both warnings.
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From: "tejohnson at google dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/60175] ICE on gcc.dg/asan/nosanitize-and-inline.c
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`175

--- Comment #4 from Teresa Johnson <tejohnson at google dot com> ---
On Fri, Feb 14, 2014 at 1:01 AM, y.gribov at samsung dot com
<gcc-bugzilla@gcc.gnu.org> wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id`175
>
> Yury Gribov <y.gribov at samsung dot com> changed:
>
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |hubicka at gcc dot gnu.org,
>                    |                            |tejohnson at google dot com
>
> --- Comment #3 from Yury Gribov <y.gribov at samsung dot com> ---
> Adding Jan and Teresa (who worked on this piece of code) to comment on proposed
> patch.

The patch looks good to me, but I can't approve. The other calls to
combine_probabilities from this module look ok to me, but this one
should be apply_probability as you note.

Thanks,
Teresa

>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

[Bug c/60195] Strange warnings using atomic types

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60195

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-02-17
                 CC|                            |mpolacek at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed.  Mine for now.

[Bug c/60195] Strange warnings using atomic types

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60195

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Wed Feb 19 06:29:49 2014
New Revision: 207873

URL: http://gcc.gnu.org/viewcvs?rev=207873&root=gcc&view=rev
Log:
    PR c/60195
c/
    * c-typeck.c (convert_lvalue_to_rvalue): Set TREE_NO_WARNING on tmp.
    Call mark_exp_read on exp.value.
    (build_atomic_assign): Set TREE_NO_WARNING on val and old.  Set
    TREE_ADDRESSABLE on old instead of val.
    (emit_side_effect_warnings): Warn only if RHS has !TREE_NO_WARNING.
testsuite/
    * gcc.dg/pr60195.c: New test.


Added:
    trunk/gcc/testsuite/gcc.dg/pr60195.c
Modified:
    trunk/gcc/c/ChangeLog
    trunk/gcc/c/c-typeck.c
    trunk/gcc/testsuite/ChangeLog

[Bug c/60195] Strange warnings using atomic types

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60195

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.9.0

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Hopefully fixed.